1. Field
Examples of embodiments relate to polishing pads and related chemical mechanical polishing apparatuses and methods.
2. Description of the Related Art
A chemical mechanical polishing process may be performed to planarize a wafer surface using a combination of a mechanical polishing effect of an abrasive and a chemical reaction effect of an alkali solution.
Generally, a chemical mechanical polishing apparatus may include a polishing head and a slurry supplying unit. The polishing head may rotate and pressurize a wafer on a polishing pad. The slurry supplying unit may feed a slurry as a polishing solution. The slurry may include the abrasive and acid and/or alkali solutions. When the slurry is fed to the polishing pad, the polishing head may grip and move the wafer to the polishing pad, and then, rotate the wafer that is in contact with the polishing pad. Thus, for example, a semiconductor material layer of the wafer may undergo chemical reactions in the acid and/or alkali solutions and may also be mechanically polished by the abrasive.
A fixed abrasive polishing pad including abrasive particles may be used for the polishing pad. The polishing pad may have polishing protrusions having hexagonal pillar shapes and arranged in a row. The polishing protrusions may include the abrasive particles. Each polishing protrusion may have a concave-shaped top surface.
As a polishing process using the polishing pad proceeds, however, edge portions of top surfaces of the polishing protrusions may wear out. Accordingly, a contact area between a polishing protrusion and the wafer may gradually increase, and thus, polishing characteristics (such as a polishing rate of the wafer, scratching, a polishing profile of the wafer, etc.) may change due to increased contact area. Therefore, it may be difficult to polish a wafer uniformly.